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{{Infobox aircraft
 |name = I-2
 |image = File:Grigorovich I-2.jpg
 |caption =
 |type = Fighter
 |manufacturer = 
 |designer = [[Grigorovich (design bureau)|Grigorovich]]
 |first_flight = 4 November 1924
 |introduction =
 |retired =
 |status =
 |primary_user = [[Soviet Air Forces]]
 |more_users =
 |produced =
 |number_built =
 |unit cost =
 |developed_from = [[Grigorovich I-1]]
 |variants =
}}

The '''Grigorovich I-2''' was a [[biplane]] [[fighter aircraft]] of the Soviet Union, the first indigenous fighter to enter service in substantial numbers.<ref>{{Cite web|url=http://www.aviation.ru/DG/#I-2|title=D. Grigorovich|date=April 3, 2005|archive-url=https://web.archive.org/web/20050403173930/http://www.aviation.ru/DG/#I-2 |archive-date=2005-04-03 }}</ref>

The I-2 was developed from the prototype [[Grigorovich I-1]]. Construction of the initial aircraft was started on February 1, 1924 and finished September 6, 1924, with A.I.Zhukov as the test pilot on the maiden flight on 4 November 1924. The aircraft was fitted with a 400&nbsp;hp [[Liberty L-12|Mikulin M-5]] and was found to be 20&nbsp;km/h faster than the I-1 with improved engine cooling. Zhukov noted that the I-2 handled well, easy to land, and required a short runway for takeoff. After improvements to load-bearing surfaces, steering, and other control systems, Zhukov noted that at low throttle it suffered from random nose lift and had a tendency to dive when accelerating. He refused to continue testing after the sixth flight. The I-2 was produced at the [[Dux Factory]], with 52 aircraft completed before being supplanted by the I-2bis model. These aircraft entered service with the flight school at [[Borisoglebsk (air base)]] in 1929.<ref>{{Cite web|url=https://www.armedconflicts.com/Grigorovich-I-2-t44267|title=Grigorovich I-2 : Grigorovich|date=February 17, 2016|website=Armedconflicts.com}}</ref><ref>{{Cite web|url=http://www.ctrl-c.liu.se/misc/RAM/i-2grigo.html|title=I-2, D.P.Grigorovich|date=February 6, 2012|archive-url=https://web.archive.org/web/20120206214812/http://www.ctrl-c.liu.se/misc/RAM/i-2grigo.html |archive-date=2012-02-06 }}</ref><ref name="auto">{{Cite web|url=http://www.airwar.ru/enc/fww1/i2.html|title=Уголок неба ¦ Григорович И-2|website=www.airwar.ru}}</ref>

Pilots M. M. Gromov and V. N. Filippov flew the I-2 on 19 November 1924 and did not note these same tendencies to nose lift or dive. They did, however, complain about the cramped cockpit as they were of average height and thus taller than Zhukov. Complaints also included the difficulty of entering and exiting the cockpit, the restricted view, and the location of the control pedals and weapon controls. As a result the I-2 was redesigned at the [[Smolensk Aviation Plant|Aviation Repair Plant No.3]]. The seat height was increased, cockpit opening enlarged, and a different engine cowling was installed. The central and front fuselage now incorporated welded steel frame for strength, as well as an improved 420&nbsp;hp engine. Due to these modifications the aircraft was given the new designation of I-2bis.<ref name="auto2">{{cite web | url=http://www.ctrl-c.liu.se/misc/RAM/i-2bis.html | archive-url=https://web.archive.org/web/20120825103149/http://www.ctrl-c.liu.se/misc/RAM/i-2bis.html | archive-date=2012-08-25 | title=I-2bis, I-2' by D.P.Grigorovich }}</ref><ref name="auto1">{{Cite web|url=https://www.armedconflicts.com/Grigorovich-I-2-bis-t44268|title=Grigorovich I-2 bis : Grigorovich|date=August 30, 2006|website=Armedconflicts.com}}</ref>

Pilots of the I-2bis noted several issues, including landing gear failures, clogged radiators, tight controls, and a tendency for the nose to lift on accelerating. As the [[Polikarpov I-3]] was still in development, the decision was made to continue with production. The first two production I-2bis were assigned to the 15th aviation brigade in [[Bryansk]] in middle of 1928, with the number increased to 10 by the end of 1928. In 1929 a report stated that the bis had heavy and inert controls, a steady dive, and significant slippage when landing. They also complained that the cockpit visor was too small for the cutout. By the end of 1929 209-211 I-2 & I2-bis aircraft were produced, with the last plane delivered in May 1931.<ref name="auto"/><ref name="auto1"/>

A number of aircraft, including I-2bis models, were sold to [[Iran]] in 1928. Eight of the I-2bis (2116-2123) were armed with [[Vickers machine gun]]s and larger radiators. What happened to those aircraft remains unknown. Due to the increased cooling issues with the I-2bis model, some aircraft were equipped with Lamblin radiators. These were given an unofficial designation of I-2', but this decreased performance even further. An experimental model of the I-2bis with a 450&nbsp;hp [[Lorraine-Dietrich aero-engines|Lorraine-Dietrich]] engine was rejected due to the size of the engine's cross-section.<ref name="auto2"/><ref name="auto"/>

==Operators==
;{{USSR}}
* [[Soviet Air Forces]]

==Specifications (I-2bis)==
{{Aircraft specs
|ref=<ref name="auto"/><ref name="auto1"/>
|prime units?=met
<!--
        General characteristics
-->
|crew=1
|length m=7.32
|length note=
|span m=10.8
|span note=
|height m=3
|height note=
|wing area sqm=23.4
|wing area note=
|aspect ratio=<!-- sailplanes -->
|airfoil=
|empty weight kg=1152
|empty weight note=
|gross weight kg=1575
|gross weight note=
|max takeoff weight kg=
|max takeoff weight note=
|fuel capacity=
|more general=
<!--
        Powerplant
-->
|eng1 number=1
|eng1 name=[[Mikulin M-5]]
|eng1 type=V-12 water-cooled piston engine
|eng1 kw=313
|eng1 note=

|prop blade number=2
|prop name=fixed-pitch propeller
|prop dia m=<!-- propeller aircraft -->
|prop dia note=
<!--
        Performance
-->
|max speed kmh=235
|max speed note=
|cruise speed kmh=
|cruise speed note=
|stall speed kmh=
|stall speed note=
|never exceed speed kmh=
|never exceed speed note=
|minimum control speed kmh=
|minimum control speed note=
|range km=600
|range note=
|combat range km=
|combat range note=
|ferry range km=
|ferry range note=
|endurance=<!-- if range unknown -->
|ceiling m=5340
|ceiling note=
|g limits=<!-- aerobatic -->
|roll rate=<!-- aerobatic -->
|climb rate ms=7
|climb rate note=
|time to altitude=
|wing loading kg/m2=67
|wing loading note=
|fuel consumption kg/km=
|power/mass={{cvt|0.19|kW/kg}}
|more performance=
<!--
        Armament
-->
|guns= 2 × 7.62 mm [[PV-1 machine gun]]s
}}

==References==
{{reflist}}

==See also==
{{aircontent|
|related=
* [[Grigorovich I-1]]
|similar aircraft=
|lists=
* [[List of interwar military aircraft]]
* [[List of military aircraft of the Soviet Union and the CIS]]
* [[List of fighter aircraft]]
|see also=
}}

{{Grigorovich aircraft}}
{{Soviet fighter designations}}

[[Category:1920s Soviet fighter aircraft]]
[[Category:Grigorovich aircraft]]
[[Category:Aircraft first flown in 1924]]